The present invention relates to nucleic acid chemistry, and more specifically to reagents and methods for accomplishing multiplex image analysis of chromosomes and chromosomal fragments. The invention may be used to diagnose chromosomal abnormalities, infectious agents, etc.
The determination of the presence and condition of chromosomes and chromosomal fragments in a biological sample is of immense importance in the diagnosis of disease. Traditionally, such determinations have been done manually by inspecting metaphase chromosomal preparations that have been treated with specialized stains to reveal characteristic banding patterns. Unfortunately, the interpretation of such banding patterns requires substantial skill and is technically difficult. Hence, alternate methods of analyzing chromosomal presence and arrangement have been sought.
One alternative approach to the problem of chromosome identification has involved the use of labeled chromosome-specific oligonucleotide probes to label repetitive sequences of interphase chromosomes (Cremer, T. et al., Hum. Genet. 74:346-352 (1986); Cremer, T. et al., Exper. Cell Res. 176:119-220 (1988)). Such methods have been shown to be useful in the prenatal diagnosis of Down""s Syndrome, as well as in the detection of chromosomal abnormalities associated with tumor cell lines. Chromosome-specific probes of repetitive DNA that localize to discrete sub-regions of a chromosome are, however, unsuitable for analyses of many types of chromosomal abnormalities (e.g., translocations or deletions).
Ward, D. C. et al. (PCT Application WO/05789, herein incorporated by reference) discloses a chromosomal in situ suppression (xe2x80x9cCISSxe2x80x9d) hybridization method for specifically labeling selected mammalian chromosomes in a manner that permits the recognition of chromosomal aberrations. In that method, sample DNA is denatured and permitted to hybridize with a mixture of fluorescently labeled chromosome-specific probes having high genetic complexity and unlabeled non-specific competitor probes. Chromosomal images were obtained as described by Manuelidis, L. et al. (Chromosoma 96:397-410 (1988), herein incorporated by reference). The method provides a rapid and highly specific assessment of individual mammalian chromosomes. The method permits, by judicious selection of appropriate probes and/or labels, the visualization of sub-regions of some or all of the chromosomes in a preparation. For example, by using more than one probe, each specific for a sub-region of a target chromosome, the method permits the simultaneous analysis of several sub-regions on that chromosome. The number of available fluorophores limits the number of chromosomes or chromosomal sub-regions that can be simultaneously visualized.
As described in PCT Application WO/05789, a xe2x80x9ccombinatorialxe2x80x9d variation of the CISS method can be employed. In the simplest case, two fluors permit three different chromosomes or chromosomal sub-regions to be simultaneously visualized. In this variation, a hybridization probe mixture is made from a single set of probe sequences composed of two halves, each separately labeled with a different fluorophore. Upon hybridization, the two fluorophores produce a third fluorescence signal that is optically distinguishable from the color of the individual fluorophores. Extension of this approach to Boolean combinations of n fluorophores permits the labeling of 2nxe2x88x921 chromosomes.
Ried, T. et al. (Proc. Natl. Acad. Sci. (U.S.A.) 89:1388-1392 (1992), herein incorporated by reference) describes the use of an epi-fluorescent microscope equipped with a digital imaging camera and computer software to xe2x80x9cpseudocolorxe2x80x9d the fluorescence patterns obtained from simultaneous in situ hybridization with seven probes using three fluorophores. The use of wavelength-selective filters allows one to isolate and collect separate gray scale images of each fluorophore. These images can be subsequently merged via appropriate software. The sensitivity and linearity of CCD cameras surmounts the technical difficulties inherent in color film-based photomicroscopy.
Although such efforts have increased the number of chromosomes that can be simultaneously detected and analyzed using in situ hybridization methods, it would be highly desirable to define a set of fluorophores having distinguishable emission spectra to permit the simultaneous detection and analysis of large numbers of different chromosomes and chromosomal sub-regions. The present invention provides such reagents as well as methods and apparatus for their use.
The invention concerns reagents and methods for combinatorial labeling of nucleic acid probes sufficient to permit the visualization and simultaneous identification of all 22 autosomal human chromosomes and the human X and Y chromosomes, or defined sub-regions thereof. Such specific labeling of entire chromosomes or defined sub-regions thereof is referred to as xe2x80x9cpainting.xe2x80x9d The invention further concerns reagents and methods for combinatorial labeling of nucleic acid probes sufficient to permit the characterization of bacteria, viruses and/or lower eukaryotes that may be present in a clinical or non-clinical preparation.
In detail, the invention concerns a set of combinatorially labeled oligonucleotide probes comprised of a first and a second subset of probes, wherein:
(A) each member of the first subset of probes comprises a plurality of an oligonucleotide: (i) being linked or coupled to a predetermined label distinguishable from the label of any other member of the first or second subsets of probes, and (ii) being capable of specifically hybridizing with one predetermined autosomal or sex chromosome of a human karyotype;
the first subset of probes set having sufficient members to be capable of specifically hybridizing each autosomal or sex chromosome of the human karyotype to at least one member; and
(B) each member of the second subset of probes comprises a plurality of an oligonucleotide: (i) being linked or coupled to a predetermined label distinguishable from the label of any other member of the first or second subset, and (ii) being capable of specifically hybridizing with one extra-chromosomal polynucleotide copy of a predetermined region of an autosomal or sex chromosome of the human karyotype.
The invention further concerns a set of combinatorially labeled oligonucleotide probes comprised of a first subset of genotypic probes and a second subset of phenotypic probes, wherein:
(A) each member of the first subset of genotypic probes comprises a plurality of an oligonucleotide: (i) being linked or coupled to a predetermined label distinguishable from the label of any other member of the first or second subsets of probes, and (ii) being capable of specifically hybridizing with a region of a nucleic acid of a preselected bacterium, virus or lower eukaryote;
the first subset of probes set having sufficient members to be capable of distinguishing the preselected bacterium, virus, or lower eukaryote from other bacteria, viruses, or lower eukaryotes; and
(B) each member of the second subset of phenotypic probes comprises a plurality of an oligonucleotide: (i) being linked or coupled to a predetermined label distinguishable from the label of any other member of the first or second subset, and (ii) being capable of specifically hybridizing with a predetermined polynucleotide region of the chromosome of the preselected bacterium, virus, or lower eukaryote, or an extra-chromosomal copy thereof so as to permit the determination of whether the preselected bacterium, virus, or lower eukaryote exhibits a preselected phenotype.
The invention additionally concerns a method of simultaneously identifying and distinguishing the individual autosomal and sex chromosomes of a human karyotype which comprises the steps:
(I) contacting a preparation of the chromosomes, in single-stranded form, under conditions sufficient to permit nucleic acid hybridization to occur with a set of combinatorially labeled oligonucleotide probes comprised of a first and a second subset of probes, wherein:
(A) each member of the first subset of probes comprises a plurality of an oligonucleotide: (i) being linked or coupled to a predetermined label distinguishable from the label of any other member of the first or second subsets of probes, and (ii) being capable of specifically hybridizing with one predetermined autosomal or sex chromosome of a human karyotype;
the first subset of probes set having sufficient members to be capable of specifically hybridizing each autosomal or sex chromosome of the human karyotype to at least one member; and
(B) each member of the second subset of probes comprises a plurality of an oligonucleotide: (i) being linked or coupled to a predetermined label distinguishable from the label of any other member of the first or second subset, and (ii) being capable of specifically hybridizing with an a predetermined extra-chromosomal polynucleotide copy of a region of an autosomal or sex chromosome of the human karyotype.
(II) for each chromosome of the preparation hybridized to a member of the first subset of probes, detecting and identifying the predetermined label of that member and correlating the identity of the label of that member with the identity of the autosomal or sex chromosome of the human karyotype with which that member specifically hybridizes, to thereby identify the chromosome hybridized to the member;
(III) repeating step (II) until each autosomal and sex chromosome of the human karyotype has been identified in the preparation
(IV) for each member of the second subset of probes hybridized to a predetermined extra-chromosomal polynucleotide copy of a region of an autosomal or sex chromosome detecting and identifying the predetermined label of that member and correlating the identity of the label of that member with the identity of the region of the autosomal or sex chromosome of the human karyotype with which that member specifically hybridizes, to thereby identify the region of the autosomal or sex chromosome hybridized to the member;
(V) repeating step (IV) for each member of the second subset of probes.
The invention additionally concerns a method of simultaneously identifying and distinguishing a preselected bacterium, virus, or lower eukaryote from other bacteria, viruses or lower eukaryotes that may be present in a sample which comprises the steps:
(I) contacting a preparation suspected to contain the preselected bacterium, virus, or lower eukaryote, under conditions sufficient to permit in situ nucleic acid hybridization to occur, with a set of combinatorially labeled oligonucleotide probes comprised of a first subset of genotypic probes and a second subset of phenotypic probes, wherein:
(A) each member of the first subset of genotypic probes comprises a plurality of an oligonucleotide: (i) being linked or coupled to a predetermined label distinguishable from the label of any other member of the first or second subsets of probes, and (ii) being capable of specifically hybridizing with a region of a nucleic acid of the preselected bacterium, virus or lower eukaryote;
the first subset of probes set having sufficient members to be capable of distinguishing the preselected bacterium, virus, or lower eukaryote from other bacteria, viruses, or lower eukaryotes present in the preparation; and
(B) each member of the second subset of probes comprises a plurality of an oligonucleotide: (i) being linked or coupled to a predetermined label distinguishable from the label of any other member of the first or second subset, and (ii) being capable of specifically hybridizing with a predetermined polynucleotide region of the nucleic acid of the preselected bacterium, virus, or lower eukaryote, or an extra-chromosomal copy thereof so as to permit the determination of whether the preselected bacterium, virus, or lower eukaryote exhibits a preselected phenotype.
(II) for each member of the first subset of probes hybridized to a region of a chromosome of a preselected bacterium, virus or lower eukaryote, detecting and identifying the predetermined label of that member and correlating the identity of the label of that member with the identity of the bacterium, virus or lower eukaryote with which that member specifically hybridizes, to thereby identify the bacterium, virus or lower eukaryote hybridized to the member;
(III) repeating step (II) for each member of the first subset of probes;
(IV) for each member of the second subset of probes hybridized to a predetermined polynucleotide region of the chromosome of the preselected bacterium, virus, or lower eukaryote, or an extra-chromosomal copy thereof, detecting and identifying the predetermined label of that member and correlating the identity of the label of that member with the identity of the predetermined region, to thereby identify the presence of the predetermined region on a chromosome of the preselected bacteria, virus or lower eukaryote;
(V) repeating step (IV) for each member of the second subset of probes.
The invention particularly contemplates the embodiments in which the members of the above sets of probes are detectably labeled with fluorophores, and, wherein at least one member of the set is combinatorially labeled with either one, two, three, four or five fluorophores selected from the group consisting of the fluorophores FITC, Cy3, Cy3.5, Cy5, Cy5.5 and Cy7, and wherein each member of the set is labeled with at least one fluorophore selected from the fluorophore group.
The invention additionally provides a set of combinatorially labeled oligonucleotide probes, each member thereof: (i) having a predetermined label distinguishable from the label of any other member of the set, and (ii) being capable of specifically hybridizing with a telomeric region of one predetermined autosomal or sex chromosome of a human karyotype; the set having sufficient members to be capable of specifically hybridizing each autosomal or sex chromosome of the human karyotype to at least one member.
The invention additionally provides a method of simultaneously identifying and distinguishing the individual autosomal and sex chromosomes of a human karyotype which comprises the steps:
(a) contacting a preparation of the chromosomes, in single-stranded form, under conditions sufficient to permit nucleic acid hybridization to occur with a set of combinatorially labeled oligonucleotide probes, each member thereof: (i) having a predetermined label distinguishable from the label of any other member of the set, and (ii) being capable of specifically hybridizing with a telomeric region of one predetermined autosomal or sex chromosome of a human karyotype; the set having sufficient members to be capable of specifically hybridizing each autosomal or sex chromosome of the human karyotype to at least one member; wherein the contacting thereby causes at least one of each autosomal or sex chromosome of the preparation to become hybridized to at least one member of the set of probes;
(b) for each chromosome of the preparation hybridized to a member of the set of probes, detecting and identifying the predetermined label of that member and correlating the identity of the label of that member with the identity of the autosomal or sex chromosome of the human karyotype with which that member specifically hybridizes, to thereby identify the chromosome hybridized to the member; and
(c) repeating step (b) until each autosomal and sex chromosome of the human karyotype has been identified in the preparation.